Firearm having internally sealed breech block



y 1967 w. A. ROBINSON 3,320,856

FIREARM HAVING INTERNALLY SEALED BREECH BLOCK Filed Oct. 19, 1965 674 49 3/ INVENTOR. 7O 9 WILLIAM A.RoBmsoN 4 A A TTORNE Y United States Patent M 3,320,&56 FIREARM HAVING INTERNALLY SEALED BREECH BLOCK William A. Robinson, R0. Box 242, Towaco, NJ. 07082 Filed Oct. 19, 1965, Ser. No. 407,862 7 Claims. (Cl. 8917) The present isvention relates to firearms and ordnance. More particularly, it relates to firearms and ordnance having an internally sealed breech block construction.

In previously proposed conventional firearms the muzzle velocity of the projectile is limited by the maximum permissible pressure in the firing chamber. Typi cally, a maximum firing chamber pressure for firearms is on the order of 55,000 p.s.i. This limitation is imposed primarily by the nature of the cartridge cases normally used with conventional breech closing devices.

The present invention relates to a novel breech-sealing structure which typically permits substantially increased firearm-operating pressures and concomitant higher muzzle velocities.

In accordance with the present invention, an explosiveoperated firearm comprises a rifled barrel open at its discharge end and sealed at its loading end by means defining a firing chamber, means refining a breech opening adapted to admit through said breech opening and into said barrel at its loading end a projectile to be fired from said firearm, a valve seat disposed on an internal wall of said firing chamber around said breech opening between said breech opening and said firing chamber, a movable breech-block adapted to mate with the seal against said valve seat from inside the firing chamber, an operating member of cross-sectional area smaller than said breech opening carrying said breech block and extending therefrom through said breech opening to a mount disposed externally of said firing chamber, driving means normally disposed externally of said firing chamher for reciprocating said operating member on said mount to carry said breech block away from said valve seat and into said firing chamber in order to open said breech opening to permit loading of a projectile therethrough into the loading end of said barrel, means normally urging said breech block against said seat, and means for firing an explosive charge within said firing chamber, whereby an explosion of an explosive charge within said firing chamber, said breech block is further urged against said seat by the pressure of the explosion, thereby utilizing the firing chamber pressure to cooperate in maintaining a gas-tight seal of the breech opening.

Various features of the instant invention will appear more fully hereinafter from a consideration of the following description, when taken in connection with the accompanying drawing which represents but one embodiment of the invention.

In the drawing:

FIG. 1 is a cross-sectional view in elevation of a firearm embodying the instant invention in condition to be fired;

FIG. 2 is a cross-sectional view in elevation of the firearm of FIG. 1 in loading condition;

FIG. 3 is a plan view, partially in section and partially broken away, of the firearm of FIG. 1 taken along the line 33 thereof;

FIG. 4 is a partial view on an enlarged scale of the firearm of FIG. 2 taken along the line 44 thereof;

FIG. 5 is a view, on an enlarged scale, in cross-section of the barrel of the firearm of FIGS. 1-3; and

FIG. 6 is a schematic diagram of the electrical circuitry associated with the firearms of FIGS. 1-3.

3,320,855 Patented May 23, 1967 In FIGS. 1-6 a U-shaped frame 10 is mounted on a stock 12. A firing chamber 14 is defined by the walls of a. firing block 16 which is mounted on the frame 10. The rear wall of the firing block 16 also defines a circular breech opening 22 which is in axial alignment with a rifled barrel (indicated generally by reference character 24), which projects from the forward wall of the firing block. The rear end of the barrel, which is closed by the firing block, is adapted to receive and accept bullets or projectiles 26 and 26a to be fired by the firearm.

As is more clearly seen in FIG. 5, the barrel 24 consists of an outer sleeve 28 which is heat shrunk about a liner 30, the liner being rified as shown in FIG. 5. As

will be observed, the lands 29 of the rifiing are considerably shallower and narrower than those employed on conventionally rifled firearms. Typically, the instant lands will have a height of about 0.001 to 0.0015 inch, and the lands and grooves 31 will be of substantially the same circumferential width, a typical barrel for a firearm of from 0.10 to 0.25 caliber having on the order of about 20 of each.

Referring again particularly to FIGS. 1-3, a beveled sealing surface or seat 32 is formed on the internal wall of the firing block 16, the seat constituting a continuation of the breech opening 22. A breech block 35 is mounted on a pivot elbow which extends through the breech opening 22, the breech block 35 being in the form of an enlarged head, the rear surface 42 of which engages and mates with the valve seat 32.

The pivot elbow 40 is of substantially smaller crosssectional area than the breech opening 22. The elbow extends from the rear of the breech block 35 through the breech opening to a pivot 44, and as may readily be seen in the drawing, defines a slightly acute angle, the pivot 44 being substantially laterally displaced from the common axis of the barrel 24 and breech opening 22. As a result, on forward motion of the pivot elbow 40, the enlarged breech block head 35 is moved forward and upwardly out of the path between the breech opening 22 and the inner end of the rifled barrel 30.

As is more clearly illustrated in FIG. 4, the pivot elbow 40 is concavo-convex in cross-section along that portion of its lower arm 41 which enters the breech opening 22 when the pivot elbow is moved to the loading position illustrated in FIG. 2. This effective concentricity makes available a maximum possible cross-sectional area when the breech opening is so opened (to permit entry of a loader into the firing chamber).

An electrode 44- projects from a spark plug 48 into close proximity of the rear of the projectile 26.

A plate 50 is bolted to the top of the firing block 16 and serves to provide a mount for the pivot 44 and also to clamp in place against the firing block a leaf spring 52 which normally urges the pivot elbow 4-0 to the position illustrated in FIG. 1 in which the rear surface 42 of the breech block 35 is firmly engaged With the seat 32, thus closing the firing chamber 14 in a gas-tight manner. An upward extension 5'4 of the upper arm 55 of the pivot elbow 40 carries an insulated electrical contact 56 which completes an electrical circuit with a second insulated electrical contact 58 mounted on a stud 60 when the pivot 40 is in the position illustrated in FIG. 1, i.e. when the firing chamber is closed.

The insulated electrical contacts 56 and 53 are wired as an interlock (to prevent remature discharge) in electrical series with a high voltage source, the spark plug 48 and its electrode 44, the projectile 26, the barrel 24, and a second pair of electrical contacts, stationary contact 62 and movable contact 64. The stationary contact 62 is insulated from the frame and is electrically connected to one terminal of the high voltage source 91. The movable contact 64 is actuated by and mounted on an extension of a trigger 66 which is pivoted on a pin 67 in a stirrup 69 depending from the frame 10. A leaf spring 68 normally urges the trigger to the open or non firing position illustrated in the drawing. Thus it will be apparent that on actuation of the trigger 66, the electrical circuit is not completed unless the breech block 35 is in place against its seat 32, thus closing contacts 56 and 58.

Loading of projectiles 26 and 26a is accomplished by a carrier indicated generally by the reference numeral 65. The projectile carrier comprises a wheeled dolly 70 which is reciprocable between the positions shown in FIG. 1 and the position shown in FIG. 2. The dolly carries wheels 74 which ride in a track 72 supported on the frame and an auxiliary pair of wheels 76 on the forward axle 78 of the dolly. The auxiliary wheels bear on a pair of parallel rails 80, which curve upwardly at their forward end and are bridged at the top by a roller 82. The rails 80 are pivoted at their rear ends on a pivot pin 84, and the normal rearward and upward pressure of the pivot arm 40 on the roller 82 (caused by the pressure of the leaf spring 52 acting on the pivot arm) biases the rails 80 to the position shown in FIG. 1. However, on the application of forward manual pressure on the dolly 70, the dolly rides forward toward the firing chamber 14, in the track 72, as a result of which the auxiliary wheels 76 urge the parallel rails 80 downwards, lowering the roller 82 and thus driving the pivot elbow 40 forward to the ultimate position illustrated in FIG. 2. In this position, of course, the breech opening 22 is fully opened.

The forward motion of the wheeled dolly 70 serves simultaneously to open the breech opening 22 through the action of the roller 82 and to carry forward the carrier 65, within which is nested a projectile-carrying cylinder 84 and a piston 86 which are in axial alignment with the barrel 24. The carrier 65 enters the firing chamber 14 as the breech block and pivot elbow 40 are moved aside, there being no physical contact between the carrier and the pivot elbow or breech block. As the carrier continues to move forward, the projectile-carrying cylinder 84 engages the rear face of the barrel 24. Inasmuch as the cylinder 84 is spring loaded by a coil spring 88, it telescopes into the outer cylinder 90 of the carrier 65 upon continued forward travel of the carrier 65, whereas the piston 86, being rigidly aflfixed to the dolly '70, continues to drive the projectile 2611 forward into the barrel 24. Thus, on full forward motion of the wheeled dolly.70 as illustrated in FiG. 2, the breech block is moved forwardly and laterally away from the breech opening and into the firing cham ber 14 and the projectile carrier 65 is telescoped by pressure exerted thereon by the rear of the barrel. The completion of forward travel of the dolly 70 and piston 86 serves to seat the projectile 16 in the rear of the barrel 24, in which it fits snugly and is held by friction as the dolly 70 and carrier 65 are manually retracted.

The projectile 26 is caseless, consisting of a bullet 92 having a button of solid propellant charge 94 afiixed to' its rear. The solid propellent is relatively insensitive to pressure, thus facilitating handling and loading in the manner described. The bullet, best seen in PEG. 6, suit ably is fabricated in the form of a solid steel body 94.

On operation of the firearm, a projectile 26a is inserted manually into the open end of the cylinder 84. The projectile is then charged to the rear of the barrel 24 in the aforedescribed manner, i.e. by manual operation of the carrier 65. The carrier is manually retracted from the firing chamber and breech opening to the position illustrated in FIG. 1. On removal of the carrier, the leaf spring 52 closes the breech block 35 in the breech opening 22 in a gas-tight manner and the firearm assumes the condition illustrated in FIG. 1 in which interlock contacts 56 and 58 are closed. To fire the firearm, finger pressure is then applied to the trigger, closing the electrical contacts 62 and 64 which, as shown in FIG. 6, are in series with a source of electrical high voltage 91, the interlock contacts 56 and 58, the spark plug 48 and electrode 44, the projectile 26, and the barrel 24. Completion of the electrical circuit on closing of the trigger contacts 62 and 64 causes an electrical discharge to jump from the tip of the electrode 44 to the projectile 26 and ignites the solid propellent 94 on the rear of the projectile. On explosion, the propellent generates a firing charm ber pressure of about 70,000 p.s.i.

As is readily apparent from inspection of FIG. 1, on development of pressure within the firing chamber 14 the breech block 35 is urged by that pressure into an even tighter seal with the valve seat 32 than was previously effected by the pressure of the leaf spring 52. (Thus it is apparent that the very chamber pressure which the breech block must contain serves to urge the breech block into a tighter seal with its sealing surface.) The contained high pressure is then utilized to expel the bullet 26 through the rifled barrel 24 at velocities substantially greater than those presently realized with conventional firearms.

As a result of the greatly increased pressures at which the instant firearm operates, e.g., 65,000l00,000 p.s.i., several significant changes from conventional practice are encountered. For example, the greatly increased pressures involved necessitate the use of solid steel or other non-extruding projectiles which will not flow readily at pressures on the order of 100,000 p.s.i. The projectile suitably is a solid bullet having a compressive yield strength of about 60,000 to 100,000 p.s.i., so as not to exhibit a fluid flow under the pressures of operation of the instant firearm but to deform on firing and slightly expand laterally while under maximum gas pressure at the rear of the barrel. Desirably the bullet is elastic and is not distorted beyond its elastic limit, but returns to its original diameter as it approaches the muzzle of the barrel, thus minimizing friction with the barrel and assuring maximum velocity on discharge. The use of such projectiles in turn leads to considerably less upsetting of the projectile into the lands of the rifled barrel than is commonplace with more conventional weapons. Thus, the dimensional considerations referred to hereinabove in connection with the lands is of considerable significance to the proper functioning of the instant firearm and the caseless cartridge which it employs.

It is to be understood that the invention herein illustrated and described is to be limited only by the scope of the appended claims and that various changes may be made in details of construction without departing from the true spirit of the invention. Thus, for example, bullets which are caseless and free of explosives may be employed and be fired by liquid or gaseous propellents which may be metered on to the firing chamber, ignition being accomplished by electrical discharge or other means. Similarly, the firearm is easily adapted for rapid automatic firing and in lieu of spring actuated operating members, desmodromic actuation may be employed if desired.

What is claimed is:

l. An explosive-operated firearm comprising a rifled barrel open at its discharge end and sealed at its loading end by means defining a firing chamber, means defining a breech opening adapted to admit through said breech opening and into said barrel at its loading end a projectile to be fired from said firearm, a valve seat disposed on an internal wall of said firing chamber around said breech opening between said breech opening and said firing chamber, a movable breech-block adapted to mate with and seal against said valve seat from inside the firing chamber, an operating member of cross-sectional area smaller than said breech opening carrying said breech block and extending therefrom through said breech opening to a mount disposed externally of said firing chamber,- driving means normally disposed externally of said firing chamber for reciprocating said operating member on said mount to carry said breech block away from said valve seat and into said firing chamber in order to open said breech opening to permit loading of a projectile therethrough into the loading end of said barrel, means normally urging said breech block against said seat, and means for firing an explosive charge within said firing chamber, whereby on explosion of an explosive charge within said firing chamber, said breech block is further urged against said seat by the pressure of the explosion, thereby utilizing the firing chamber pressure to cooperate in maintaining a gas-tight seal of the breech opening.

2. An explosive-operated firearm as set forth in claim 1 in which said means for firing said explosive charge is an electrical spark-generating circuit.

3. An explosive-operated firearm as set forth in claim 2 in which said circuit includes an electrical interlock which prevents firing unless said breech block is sealed 7 against said valve seat- 4. An explosive-operated firearm as set forth in claim 1 in which the breech opening is in alignment with the axis of the barrel, the amount is offset therefrom, and the operating member is an elbow having two arms, one of which pivots on the mount and the other of which carries the breech block.

5. An explosive operated firearm as set forth in claim 4 in which the breech opening is circular and the arm of the breech carrying elbow which extends through the breech opening is concavo-convex concentrically in crosssection with said breech opening for at least part of the length of the arm.

6. An explosive-operated firearm comprising a rifled barrel terminated at its loading end by a block defining a firing chamber, said block having therein a breech opening, a valve seat disposed on the wall of said firing chamber and around said breech opening, a breech block disposed within said chamber and adapted to mate with and seal against said valve seat in a gas tight manner, said breech block being mounted on a pivoted elbow which extends throug said breech opening to a pivot disposed externally of said firing chamber, means acting on said pivoted elbow for biasing said breech block to a normally closed position, and means for firing an explosive charge within said chamber, whereby on explosion of an explosive charge within said firing chamber, said breech block is further urged against said seat by the pressure of the explosion, thereby utilizing the firing chamber presture to cooperate in maintaining a gas-tight seal of the breech opening.

7. An explosive-operated firearm comprising a barrel rifled to a depth of from about 0.001 to 0.0015 inch, said barrel terminating at its loading end in a block defining a firing chamber, a caseless propellent-carrying solid metallic bullet having a compressive yield strength of about 60,000 to 100,000 p.s.i. disposed in the loading end of said barrel, said propellent being capable on explosion thereof of generating a pressure in said firing chamber of from about 65,000 to 100,000 p.s.i., a breech opening in said block, a valve seat disposed on the wall of said firing chamber and around said breech opening, a breech block disposed within said chamber and adapted to mate with and seal against said valve seat in a gas tight manner, said breech block being mounted on a pivoted elbow which extends through said breech opening to a pivot disposed externally of said firing chamber, means acting on said pivoted elbow for biasing said breech block to a normally closed position, and means for firing an explosive charge within said chamber, whereby on explosion of an explosive charge within said firing chamber, said breech block is further urged against said seat by the pressure of the explosion, thereby utilizing the firing chamber pressure to cooperate in maintaining a gas-tight-seal of the breech opening.

No references cited.

BENJAMIN A. BORCHELT, Primary Examiner.

S. W. ENGLE, Assistant Examiner. 

1. AN EXPLOSIVE-OPERATED FIREARM COMPRISING A RIFLED BARREL OPEN AT ITS DISCHARGE END AND SEALED AT ITS LOADING END BY MEANS DEFINING A FIRING CHAMBER, MEANS DEFINING A BREECH OPENING ADAPTED TO ADMIT THROUGH SAID BREECH OPENING AND INTO SAID BARREL AT ITS LOADING END A PROJECTILE TO BE FIRED FROM SAID FIREARM, A VALVE SEAT DISPOSED ON AN INTERNAL WALL OF SAID FIRING CHAMBER AROUND SAID BREECH OPENING BETWEEN SAID BREECH-BLOCK ADAPTED TO MATE FIRING CHAMBER, A MOVABLE BREECH-BLOCK ADAPTED TO MATE WITH AND SEAL AGAINST SAID VALVE SEAT FROM INSIDE THE FIRING CHAMBER, AN OPERATING MEMBER OF CROSS-SECTIONAL AREA SMALLER THAN SAID BREECH OPENING CARRYING SAID BREECH BLOCK AND EXTENDING THEREFROM THROUGH SAID BREECH OPENING TO A MOUNT DISPOSED EXTERNALLY OF SAID FIRING CHAMBER, DRIVING MEANS NORMALLY DISPOSED EXTERNALLY OF SAID FIRING CHAMBER FOR RECIPROCATING SAID OPERATING MEMBER ON SAID MOUNT TO CARRY SAID BREECH BLOCK AWAY FROM SIAD VALVE SEAT AND INTO SAID FIRING CHAMBER IN ORDER TO OPEN SAID BREECH OPENING TO PERMIT LOADING OF A PROJECTILE THERETHROUGH INTO THE LOADING END OF SAID BARREL, MEANS NORMALLY URGING SAID BREECH BLOCK AGAINST SAID SEAT, AND MEANS FOR FIRING AND EXPLOSIVE CHARGE WITHIN SAID FIRING CHAMBER, WHEREBY ON EXPLOSION OF AN EXPLOSIVE CHARGE WITHIN SAID FIRING CHAMBER, SAID BREECH BLOCK IS FURTHER URGED AGAINST SAID SEAT BY THE PRESSURE OF THE EXPLOSION, THEREBY UTILIZING THE FIRING CHAMBER PRESSURE TO COOPERATE IN MAINTAINING A GAS-TIGHT SEAL OF THE BREECH OPENING. 